package org.dawnmew.jvirtualstream;

/**
 * Creates a simple, extensible virtual filesystem capable of combining several
 * traditional filesystems and streaming sources.
 *
 * @author dawnmew
 * @since 1.0
 *
 * Licensed under the MIT License.
 *
 * Copyright (c) 2012 dawnmew
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
import java.io.InputStream;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map.Entry;

public class VirtualFileSystem
{

    private static VirtualFileSystem instance = null;
    private final Object hashLock = new Object();
    private HashMap<String, VirtualFileSystemSource> sources = new HashMap<String, VirtualFileSystemSource>();

    public static VirtualFileSystem getInstance()
    {
        if (instance == null)
        {
            instance = new VirtualFileSystem();
        }
        return instance;
    }

    public void addSource(String id, VirtualFileSystemSource source)
    {
        synchronized (hashLock)
        {
            sources.put(id, source);
        }
    }

    public void removeSource(String id)
    {
        synchronized (hashLock)
        {
            sources.remove(id);
        }
    }

    public InputStream getInputStream(String path)
    {
        synchronized (hashLock)
        {
            Iterator iterator = sources.entrySet().iterator();
            while (iterator.hasNext())
            {
                VirtualFileSystemSource source = ((Entry<String, VirtualFileSystemSource>) iterator.next()).getValue();
                InputStream is = source.getInputStream(path);
                if (is != null)
                {
                    return is;
                }
            }
        }
        return null;
    }

    public InputStream getInputStreamFromSource(String id, String path)
    {
        return sources.get(id).getInputStream(path);
    }
}
